Material conveyor

ABSTRACT

A device for conveying measured amounts of material which includes a rotating induction wheel having a plurality of elongate open-ended chambers defined therein and a pair of wipers arranged to remove excess material from the chamber ends. Pressure pads seal the chambers, and gas is introduced into the chambers to pulse the material out of the chambers into a material transport conduit. Metered charges of material are thus delivered to the transport conduit. An alternative embodiment of the metering device has a pair of sequential chambers pressurized simultaneously.

BACKGROUND OF THE INVENTION

This application is a continuation-in-part of application Ser. No.897,338, filed Apr. 18, 1976, now U.S. Pat. No. 4,179,232.

The present invention relates in general to conveying granular material,and more particularly, to conveying metered amounts of granularmaterial.

Many systems employ granular or pulverulent material. Examples of suchsystems are dry cement handling systems, hopper container unloadingsystems, and the like.

Some of the systems used to move granular material from one location,such as a hopper or other storage device, to another location arerequired to deliver such granular material in metered amounts. Themetered amounts can take the form of a controlled flow rate or the formof metered charges.

The inventor is aware of several devices which deliver metered amountsof granular material. Examples of such known devices are disclosed inU.S. Pat. Nos. 2,740,672, 2,890,079, 3,009,744 and 3,268,266. While allof the devices disclosed in these patents are somewhat efficient, theyall suffer from drawbacks resulting from inefficient and inaccuratelydelivered material. The size of the charges of material delivered bythese devices often varies beyond limits required for great accuracy,and such inaccuracies are not easily corrected, if they are correctableat all. Furthermore, some of the granular material delivered to thesedevices may be crushed by the device. Such crushed material may causeinaccuracies in the processes using the material delivered by thedevice.

SUMMARY OF THE INVENTION

The device embodying the teachings of the present invention comprises ahopper body, and granular material enters that body through the topthereof. An induction wheel is mounted within the hopper body to rotatein a vertical plane in a direction opposite to the influx of granularmaterial. The wheel scoops up material from a reservoir formed on thebottom of the hopper by the inflowing material, and carries thatmaterial upwardly. The wheel includes a plurality of elongateladle-shaped chambers which are open at both ends thereof and which areloaded via both of those open ends. The chambers are generallyoverfilled during the transit thereof through the reservoir, and excessmaterial spills out of the chambers through the open ends back into thereservoir before the chambers reach the twelve o'clock position on thewheel. The speed of wheel rotation, level of the reservoir, size of thechamber openings and the like are adjusted so that nearly all of theexcess material is spilled out of the chamber during this phase ofoperation. Such spilling avoids damage to the material.

The device includes a pair of tandem wipers mounted on the housing nearthe twelve o'clock position of the wheel to gently remove any remainingexcess material located at the chamber ends and protruding thereoutof.

A pair of air retaining pads are each mounted on opposite sides of thewheel and contact the wheel after that wheel has passed the positionwhereat the chamber of interest is at the twelve o'clock position. Thepads seal the chambers.

A pair of longitudinally aligned ports are mounted in the housing and agas induction conduit and a material transport conduit are connected tothose ports to be in longitudinally aligned relationship on the housing,so that the induction wheel is located therebetween. The chambers aresequentially longitudinally aligned with the conduits, and high pressuregas, such as air, or the like, is inducted into the chambers via the gasinduction conduit, and exhausted into the transport conduit on the otherside of the chamber to force the material out of the chamber into thattransport conduit. The material is then transported to a suitablelocation in that transport conduit.

By being loaded from both ends, the chambers are efficiently loaded, andthe spillage therefrom can be controlled to occur at a desiredsequential position of the chamber on the wheel, and at desired times inthe operation. Thus, the size of the charge contained within eachchamber is accurately controlled and spillage therefrom occurs at themost propitious time. The device of the present invention thus deliversprecise charges of material and operates in a manner not likely todamage the material so that waste is eliminated, or at least minimized,as compared to prior devices.

The pads of the present invention seal the chambers and thus insure thatgas is not wasted through leakage out of the chambers, thereby producingefficient and precise use of gas. Such gas usage further enables precisecontrol of charge size, as leakage in the charge moving gas upstreameffects flow rates therein, as well as the amount of material actuallyremoved from the chamber. In the limit, maximum leakage may even causethe gas pulse into the chambers of prior devices to fail to remove anyof the charge, thereby rendering these device completely inoperative.The pads of the present invention seal the chambers and thus minimizeleakage to maximize the accuracy of the gas pulse delivery and hence theprecision with which the charge is removed from a chamber. Precision atthe initial point in the delivery process permits the rest of thedelivery process to be accurate.

As material in the induction wheel is being carried upwardly, materialspilling out of the chambers is gravity assisted and thus the device ofthe present invention takes advantage of gravity rather than opposingit. The efficient removal of excess material thus not only improves theprecision of the present device over that of the prior art, but hasmaximum life of the elements thereof, such as the pads, due to theremoval of abrasive materials prior to contact with the pads.

The device of the present invention is quite amenable to use with alarge variety of power systems, thereby increasing the flexibilitythereof over prior devices.

An alternative embodiment of the metering device includes a pair ofpressurizing conduits located to pressurize a pair of sequentialchambers at the same time and thus at least two chambers are pressurizedat all times. The alternative embodiment also includes an air padretaining unit which holds the air pads in position and does not requireany adjustments thereto.

OBJECTS OF THE INVENTION

It is therefore a main object of the present invention to conveygranular material in an accurately metered manner.

It is another object of the present invention to convey granularmaterial in a manner which prevents excessive waste of such material.

It is a further object of the present invention to convey granularmaterial in a manner which efficiently utilizes the high pressure gasused in the material transport system.

It is still another object of the present invention to convey granularmaterial using a device having elements which are arranged to reducewear and abrasion thereon.

It is still a further object of the present invention to convey granularmaterial using a device having chambers which are efficiently loadedwith a charge of material the size of which is accurately set.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming part hereof, wherein likereference numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially cut away perspective of the granular materialconveying device embodying the teachings of the present invention.

FIG. 2 is a view taken along line 2--2 of FIG. 1.

FIG. 3 is a view taken along line 3--3 of FIG. 2.

FIG. 4 is a top plan view of an alternative embodiment of the conveyingdevice embodying the teachings of the present invention.

FIG. 5 is an elevation view of the alternative embodiment of theconveying device embodying the teachings of the present invention.

FIG. 6 is an exploded perspective of an air pad retaining housing usedin the alternative embodiment of the conveying device embodying theteachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Shown in FIG. 1 is a metering device 10 which conveys metered amounts ofgranular material to a material transport line 12. The device 10includes a housing 14 which includes a bottom 16, upstanding sides 18, aback 19, a front 20, and a top 22. A material entrance 26 is defined inthe top 22 near one of the sides 18. As shown in FIG. 2, material, suchas pulverulent or granulated material G is discharged from a source (notshown) such as a hopper, or the like, into the housing 14 via theentrance 26. The material G gravitates downwardly in freefall from theentrance as indicated by the arrow D and collects on the bottom of thehousing to form a reservoir as indicated in FIG. 2 by the indicator R.The reservoir is located in a lower section of the housing and will bemore fully discussed below.

The metering device includes a U-shaped bracket 30 having a base section32, a top section 34 and a vertically oriented bight section 36. Thebracket is mounted along the outer peripheral edge 40 of base 32 oninner surface 42 of the bottom 16 and along the outer peripheral edge 46of the top 34 on the inner surface 48 of the top 22. The front edges 50of the legs are each mounted on the inner surface 52 of the housingfront 20, and the outer peripheral edge 56 is mounted on inner surface58 of the housing back. The bracket 30 is thus securely mounted in thehousing to retain the vertical on-edge orientation shown therefor inFIG. 1. The bracket 30 is located to be just off center and therebydivide the housing contained volume into two unequal sections.

A vertically revolving induction wheel 60 is mounted on a shaft 62 forrotation therewith. The shaft 62 is horizontally disposed and extendsthrough the housing front and back walls. The shaft 62 is suitablyjournalled in those walls to be freely rotatable and is connected to asuitable power source (not shown) to be rotated thereby. Clockwiserotation of the wheel 60 is preferred and is indicated in FIG. 2 byarrow C. The clockwise rotation of the wheel 60 is counter to thedownward flux of the material G and thus is least disruptive thereof andis least disturbed thereby.

The wheel 60 has a pair of side faces 64 and 66 (see FIG. 3) and a rim68 connecting those two faces. A multiplicity of circumferentiallydisposed ladle-shaped chambers 70 are defined in the wheel to extendaxially thereof and to be located adjacent, but spaced from, the rim 68.Each chamber has an inner wall 72 which is arcuate and positioned sothat the walls 72 of the multiplicity of chambers define a generatrix ofa circle which is concentric with the circular rim 68. The chambers eachhave a top wall 76 which is essentially straight and skewed with respectto a radial direction of the wheel to lie on a nondiametric secant ofthe wheel 60. The inner and outer walls are connected by aparabolically-shaped wall 78 which has a bulge 80 in the outermostsection thereof. The chambers 70 are open-ended and scoop out material Gfrom the reservoir R as the wheel 60 turns.

As an empty chamber is immersed in the reservoir, the material issufficiently fluent to move into that chamber via both empty endsthereof. The chambers are suitably sized, the rotational velocity andcontinuity of the rotation of the wheel is selected, and the depth ofreservoir R is adjusted via adjustment of the influx timing and ratethrough housing entrance 26, so that, upon emerging from the reservoir,the chambers will all contain roughly the same charge of material,indicated by the reference indicator M in FIG. 2. As the wheel rotates,some of the material will drop out of the chambers, and the varioussizes of the charges are indicated in FIG. 2 as M' and M".

A tandem pair of wipers 86 and 88 are located on each side of the wheelto flushly engage the wheel sides 64 and 66. As shown in FIG. 2, thewiper 86 is attached to surface 48 of top 22 and has a forward surface92 which is downwardly depending therefrom and has a rear surface 94which intersects the forward surface and is upwardly inclined therefrom.A vertical surface 96 connects the rear surface to the surface 48. Thewiper forward surface 92 may be slanted outwardly from the wheel and thewiper removes excess material from the chambers, and that removedmaterial falls back into the reservoir.

The wiper 88 is attached to surface 100 of the bracket bight section 36and extends outwardly therefrom. The wiper 88 has a lower surface 102, afront edge 104 which is essentially vertical, and a forward surface 106which is upwardly inclined from the front edge. A top surface 108 isessentially horizontal and connects the forward surface to the bightsurface 100. The forward surface 106 is positioned to be in spacedparallelism with the lower surface 94 of the wiper 86, and serves toassist in the removal of excess material from the chambers as thosechambers move therepast.

A similar pair of wipers is located adjacent wheel side 64, but is notshown for the sake of clarity. The wipers remove excess material so thatmaterial is not damaged during operation of the device 10. Without thewipers, some of the material would be destroyed, and hence wasted.

A pair of L-shaped brackets 120 and 122 are mounted on surface 124 ofthe bracket bight section 36. The brackets 120 and 122 are in spacedparallelism and each has a web section 126 which extends outwardly fromthe bight section. A plurality of fasteners, such as bolts 130, areconnected to the bracket webs to extend horizontally toward the centerof the housing. As shown in FIG. 1, there are two pairs of L-bracketswith the wheel 60 being located therebetween. A pair of pad backingmembers 140 and 142 are attached to the L-brackets by the bolts, andeach pad backing member has a pad 144 thereon. The pads 144 arevertically oriented, are in spaced parallelism with each other, and eachcontacts one of the surfaces 64 and 66 of the wheel 60 to occlude thechambers 70. The pads obstruct the chambers in an air-tight manner and apair of springs 150 and 152 surround the endmost bolts of each L-shapedbracket to bias the pads against the wheel surfaces with a constant andsteady pressure which is sufficient to insure air-tightness of therubbing engagement between the pads and the wheel without inducing unduewear on the pads or unduly inhibiting rotation of the wheel 60. Asjust-discussed, the wipers remove excess material, and, without suchexcess material removal, some of the material may become lodged betweenthe wheel and the pads 144 and be crushed. Such material not only iswasted, but may abrade both the wheel and the pads, thereby reducing thelife and effectiveness of those elements.

As best shown in FIG. 3, a pair of axially aligned conduit attachingmeans 170 and 172, respectively, are attached to the pads and padbacking members to extend horizontally away from the wheel 60. An airinlet conduit 176 is fluidly connected to member 170 and a materialtransport conduit 178 is fluently attached to member 172 for conveyingthe material to a suitable location. Air from a suitable source (notshown) is directed to the chambers 70 via conduit 176 in member 170. Avent tube 180 is mounted on the pads and pad backing members immediatelybehind (in the clockwise direction of wheel rotation) the member 176. Asthe pads cover the chambers in an air-tight manner, air conducted intothe chamber via airline 176 will pressurize that chamber. The air passesthrough the chamber and into conduit 178 carrying with it the materialcontained within the chamber. As the chamber contains a specificquantity of material, the amount of material pulsed into conduit 178from each of the chambers is an accurately metered quantity.

The chamber may not completely vent into outlet line 178 and may thusmove beyond the material transfer point in line with the alignedconduits 176 and 178 still under an excess pressure. This excesspressure is relieved via vent valve 180.

The operation of the metering device 10 is evident from the abovedescription and will thus only be briefly presented. The rotation of thewheel 60 can be continuous, sequential, or continuous with a dwellperiod, as suitable. In any event, the chambers 70 are each filled fromboth ends thereof to overflowing as they are moved through the reservoirR, and some of the material spills out as the wheel rotates theoverfilled chamber upwardly out of the reservoir. By loading thechambers from both sides, complete loading of the chambers is insured.The level of the reservoir is maintained so that the top surface thereofis always located below the axis of rotation of the wheel and at alocation selected to insure proper spillage rates from the chambers. Bymoving upwardly through the reservoir, the ladle-shape of the chambersis fully utilized in a scooping action. Thus, gravity assists in theloading of the chambers.

The wipers 86 and 88 on both sides of the wheel remove excess material,and the quantity of material remaining in each chamber is thus uniform,and hence accurately metered. The chambers are then moved between thepads 140 and 142 and closed in an air-tight manner. Each chamber then issequentially moved into alignment with the conduits 176 and 178, whereata blast of air, or other suitable gas, is directed into the interior ofthe chamber. At this point, a pause in wheel rotation can be effectedusing appropriate timing, or mechanical means, or the like, to permitthe full charge of material to be exhausted into line 178 via member 172by the gas moving from conduit 176 through chamber 70 and into the line178.

Continued rotation of the wheel 60 then aligns the material exhaustedchamber with vent valve 180, whereat any excess unexhausted gas stillcontained in the chamber is vented therefrom. Continued rotation of thechamber brings the chamber back into contact with the reservoir R, andthe above-described process reoccurs. Any material not exhausted fromthe chamber simply remains in the chamber and forms part of the nextcharge in the chamber. However, the sequential operation of the elementscan be adjusted to prevent such residue, as the presence thereof changesthe volume of the meter charges delivered by the device 10. If thesecharges must be accurately controlled, the existence of such residue is,of course, undesirable, but as just-discussed, can be prevented byadjusting the elements of the device 10 and the sequence of operationthereof.

The just-described process is repeated as often as desired and at asuitable rate to produce a desired rate of material flow through conduit178. The conduit 178 can also be connected to a suitable suction meansto assist in conveying material through that conduit. The suction willthus work in conjunction with the air pressure produced via conduit 176to move the material through conduit 178 to the desired location.

The device 10 is amenable to systems involving several different typesof power. Thus, the wheel 60 can be rotated using electric motors,internal combustion engines, or the like.

Shown in FIGS. 4, 5 and 6 is an alternative embodiment of the meteringdevice which embodies the teachings of the present invention. The deviceis denoted by the reference numeral 10' and includes a housing 14'similar to the housing of device 10, but which has some differences,which will become apparent from the following description, toaccommodate the elements of the alternative embodiment. The meteringdevice 10' includes a pair of air inlet conduits 176' which arevertically aligned and serve to maintain at least two sequentiallylocated chambers 70 pressurized at all times. Accordingly, the housing14' differs from the housing 14 to accommodate the two air inletconduits 176'. By keeping two sequential chambers pressurized, granularmaterial is prevented from being vacuumed back into the wheel 60 as thatwheel rotates. Such back-vacuum prevention assures that essentially allof the material is discharged into the airstream.

As best shown in FIGS. 4 and 6, the metering device 10' also includes apad unit 200. The pad unit 200 holds a pair of semicircular airretaining pads 144f and 144b in a fixed position, and thus noadjustments are necessary. The unit 200 is shown in FIG. 6 to include apair of semicircular pad backing members 140f and 140b and asemicircular housing segment 204 having a flange 206 on each end of aweb section 208. The housing segment 204 surrounds the wheel 60 and thushas an inner diameter slightly larger than the outer diameter of thewheel 60 so that the wheel can rotate freely therewithin. As shown inFIG. 6, the web section, the pads and the backing members are allcorrespondingly shaped. A plurality of fasteners, such as bolts 210, aremounted on the web section to be oriented axially thereof and to extendoutwardly thereof. The flanges 206 each has a plurality of fastenerreceiving holes 212 defined therein for attaching the housing segment204 to the bracket 30 by bolts, or the like.

The pads and pad backing members each has a plurality of fastenerreceiving holes 214 and 216, respectively, defined therein to receivethe bolts 210. A fastener locking assembly 220 which includes a nut Nand a washer W is associated with each bolt to securely lock the padsand pad backing members to the housing segment.

As shown in FIG. 6, the pad 144f and the backing member 140f associatedtherewith have aligned holes 224 and 226, respectively, to correspond tothe pair of conduits 176'. A pair of conduit attaching members 170' aremounted on the pad backing member 140f to extend axially outward of thewheel 60 and to be fluidly attached to air inlet conduits 176' forconducting air into a pair of sequentially oriented chambers. Theconduit attaching members are spaced apart a distance sufficient tomaintain pressure on a pair of sequentially oriented chamberssimultaneously. As in the first embodiment, only one material transportconduit is included in the metering device 10'. Accordingly, singleapertures 230 and 232 are defined in the pad 144b and backing member140b, respectively, to fluidly connect conduit attaching member 172 tothe interior of a chamber for fluidly connecting that chamber to thematerial transport conduit as in the metering device 10.

As this invention may be embodied in several forms without departingfrom the spirit or essential characteristics thereof, the presentembodiment is, therefore, illustrative and not restrictive, since thescope of the invention is defined by the appended claims rather than bythe description preceding them, and all changes that fall within themetes and bounds of the claims or that form their functional as well asconjointly cooperative equivalents are, therefore, intended to beembraced by those claims.

I claim:
 1. A device for conveying granular material comprising:ahousing having a material entrance defined therein; an induction wheelrotatably mounted on said housing, said wheel having a plurality ofelongate open-ended chambers defined therein; a pair of wipers mountedon said housing adjacent said wheel and located so that said wheelpasses between said wipers to gently remove excess material from theends of said chambers without damaging that removed material, said pairof wipers including wipers spaced from each other to define a materialescape path through which said gently removed material passes; sealingmeans mounted on said housing to sealingly cover said chamber ends, saidsealing means including an arcuate housing surrounding said wheel andsecured to said housing, a pair of pad members secured to said housing,a pair of pad backing members secured to said arcuate housing andsprings biasing said pads against said wheel in a secure manner, saidsealing means being separate from and spaced apart from said wipers tobe located so that a chamber on said induction wheel passes between saidpair of wipers prior to passing said sealing means, said wipers removingexcess material from adjacent the ends of a chamber before such chamberis sealed by said sealing means so that material does not interfere withany seal formed between said sealing means and said chamber ends suchthat said chambers are securely closed to minimize loss of any gasintroduced into said chambers for moving material out of said chambers;gas introducing means connected to said sealing means to introduce gasfrom a source into a chamber; and material transport means connected tosaid sealing means to receive gas and material from said chambers fortransporting said material away from said induction wheel.
 2. The devicedefined in claim 1 wherein said induction wheel has a rim and saidchambers are ladle-shaped and are mounted in a circle which isconcentric with the rim of said induction wheel.
 3. The device definedin claim 1 further including a vent mounted on said sealing means forventing excess pressure from said chambers.
 4. The device defined inclaim 1 wherein said induction wheel is mounted to rotate in a verticalplane in a direction opposite to the direction of movement of materialinto said housing through said material entrance.
 5. The device definedin claim 4 wherein said entrance is located in the top of said housing.6. The device defined in claim 4 further including a reservoir ofmaterial located on the bottom of said housing.
 7. The device defined inclaim 6 wherein said reservoir has a top surface located below the axisof rotation of said induction wheel.
 8. The device defined in claim 1further including a second pair of wipers each mounted adjacent one ofsaid first pair of wipers.
 9. The device defined in claim 1 wherein saidgas introducing means includes a pair of conduits.